Posted April 13, 200718 yr I'm slightly unsure as to what section to put this topic in so mods please move this if you see fit.I'm a first semester electrical student and I'm pretty familiar with the ohms law wheel and its formulas. But, for some reason I fall short when trying to calculate the total impedances of a certain car audio circuits.My question is what formulas do you guys use to figure out all of the different ohm loads that can be used w/ corresponding VC configurations.Ex. 2 Dual 2 SubsWhat are all of the ohm loads that can be reached.I understand that anyone can go 2 the rockford fosgate wiring wizard and find a solution. But I'm more interested in how these values are derived.
April 13, 200718 yr Series: R1 + R2 + R3 + ... + RN = RtotalParallel: 1/R1 + 1/R2 + 1/R3 + ... + 1/RN = 1/Rtotal
April 13, 200718 yr Author Series: R1 + R2 + R3 + ... + RN = RtotalParallel: 1/R1 + 1/R2 + 1/R3 + ... + 1/RN = 1/RtotalYea, i knew those 2.....But how is it that whenever i see people listing impedances that they have figured they have upwards of 4 different ones?
April 13, 200718 yr those are all the combinations that one could get with a certain set of coils2 SVC or 1 DVC driver will have 2 options (series or parallel)2 DVC drivers will have 3 options (series, series or series, parallel or parallel, parallel)1 QVC driver will have 3 options (series, series or series, parallel or parallel, parallel)
April 13, 200718 yr Series: R1 + R2 + R3 + ... + RN = RtotalParallel: 1/R1 + 1/R2 + 1/R3 + ... + 1/RN = 1/RtotalThese two formulas are the only ones that can be used.So, the question is: how can you possibly have 4 or 5 different possibilities when wiring multiple subs?Well, quite simply: break it down.Let's say there are 4 dvc subs. 2 of them, we will wire in series. The other 2, we will wire in parallel. Then we will wire each sub in the group to the other the same way we wired their voice coils, ie. the first group will be wired to each other in series, the second group will be wired to each other in parallel. Lastly, we will wire the two groups together.You need to calculate each part of the circuit on it's own. To calculate the total resistance, we must know the resistance of each group first. To know the resistance of each group, we must know the resistance of each sub. To know the resistance of each sub, we must know the resistance of voice coil. If you change the way a particular step is wired, then you change the final resistance.edit: That made sense when I first typed it out, though I'm not sure it still does. Please post if you need further clarification.
April 14, 200718 yr These two formulas are the only one that can be used.wasn't sure whether to put this in my sig or just clarify that you meant
April 14, 200718 yr i did fairly well on this portion of my first engineering circuits test 3 years ago. then i fell asleep in class after that section and my circuits grade went to crap. BUT, at least i remembered how to do all this stuff and it's pretty darn simple with subs
April 14, 200718 yr These two formulas are the only one that can be used.wasn't sure whether to put this in my sig or just clarify that you meantHaha.Touche, sir.
April 14, 200718 yr Remember, when wiring in parallel, you final impedance will always be lower then you lowest resistance in the circuit. That is an easy way to make sure if you did your calculations right.
April 14, 200718 yr Remember, when wiring in parallel, you final impedance will always be lower then you lowest resistance in the circuit. That is an easy way to make sure if you did your calculations right.? detail please. as far as i know, dcr is lower than the actual impedance. too bad the drawings i made for VJ dissapeared during the data loss...makes sense to me Neil. i always have hard times explaining these things
April 15, 200718 yr OK. Say you have a 5ohm load and a 10ohm load in parallel, you final ohm load will be less then 5 ohms.1/5 + 1/10 = answer (reciprocal equation) 1/answer = impedance .2 + .1 = .3 1/.3 = 3.333It is just a fast way to make sure that you did your match correct. Edited April 15, 200718 yr by X-OvrDistortion
April 15, 200718 yr Remember, when wiring in parallel, you final impedance will always be lower then you lowest resistance in the circuit. That is an easy way to make sure if you did your calculations right.In parallel only and you needed to say lowest impedance in the circuit not lowest resistance.
April 15, 200718 yr Remember, when wiring in parallel, you final impedance will always be lower then you lowest resistance in the circuit. That is an easy way to make sure if you did your calculations right.In parallel only and you needed to say lowest impedance in the circuit not lowest resistance.That is why I said, and I quote "when wiring in parallel".
April 16, 200718 yr Remember, when wiring in parallel, you final impedance will always be lower then you lowest resistance in the circuit. That is an easy way to make sure if you did your calculations right.In parallel only and you needed to say lowest impedance in the circuit not lowest resistance.That is why I said, and I quote "when wiring in parallel".Since impedance is not resistance I thought I should clarify.
April 16, 200718 yr Since impedance is not resistance I thought I should clarify.Don't make me smack you boy!!
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